Re: [Qemu-devel] [PATCH] qemu-io: fix EOF Ctrl-D handling in qemu-io readline code

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Daniel P. Berrange (berrange@redhat.com) wrote:
> qemu-io puts the TTY into non-canonical mode, which means no EOF processing is
> done and thus getchar() will never return the EOF constant. Instead we have to
> check for an explicit Ctrl-D, aka  0x4, to detect EOF and exit the qemu-io
> shell. This fixes the regression that prevented Ctrl-D from triggering an exit
> of qemu-io that has existed since readline was first added in
> 
>   commit 0cf17e181798063c3824c8200ba46f25f54faa1a
>   Author: Stefan Hajnoczi <stefanha@redhat.com>
>   Date:   Thu Nov 14 11:54:17 2013 +0100
> 
>     qemu-io: use readline.c
> 
> Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> ---
>  qemu-io.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/qemu-io.c b/qemu-io.c
> index c70bde3eb1..2ea0bfbaf8 100644
> --- a/qemu-io.c
> +++ b/qemu-io.c
> @@ -322,7 +322,9 @@ static char *fetchline_readline(void)
>      readline_start(readline_state, get_prompt(), 0, readline_func, &line);
>      while (!line) {
>          int ch = getchar();
> -        if (ch == EOF) {
> +        /* In non-canon tty mode we get 0x4 (Ctrl-D), not the stdio "EOF"
> +         * constant */
> +        if (ch == 0x4) {

Personally I'd have made that EOF or 0x4  - but that's fine

(I don't see the point of reading the ioctl to figure out which EOF
char we're using; it seems to turn a trivial check into something much
more complex)

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

>              break;
>          }
>          readline_handle_byte(readline_state, ch);
> -- 
> 2.14.3
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK